The long range goal of this study is the understanding of the central nervous system functions regulating body temperature. The goals set for the current year included the study of ; 1. the effects of microelectrophoretically applied Prostaglandin 1E fever production in conscious rabbits in the partitional calorimeter. Research Plans for the Coming Year will; a) extend investigation of the interaction of central and peripheral thermal inputs in the regulation of preoptic neuronal activity and thermoregulatory effector outputs. b) continue investigation of the effects of microelectrophoreased PGE1 onto preoptic single units. Since we have established that PGE1 is a potent pyrogenic agent acting specifically in the preoptic area of the rabbit, we feel that this approach offers the best chance of elucidating the neuronal mechanism of fever production.